The Ruff-Wear Beacon is a Bright LED Dog Light designed to keep Dogs Visible in Low-Light Conditions. This Dog-Tested Light is Sturdy, Compact, Watertight, Lightweight, and Easy to Use. The Beacon Clips onto all Ruff-Wear Wearable Dog Gear - Collars, Packs, Apparel, Life Jackets, and Harnesses (see SKU: RFWK9OF). For Additional Safety, it also Clips to Runners, Hikers, Cyclists, Kids, and Equipment. High-Intensity LED with Light-Dispersing Lens provides a Hemisphere of Light. Three Light Modes allow Multiple Dog Tracking: Slow-Flash, Fast-Flash, and Always-On. Light has an Integrated-Clip and Quick-Ring that provides Two-Attachment-Options. The Ruff-Wear Beacon LED Dog Light is powered by two CR2032 Coin Cell Batteries (included).